Update Qt5 to 5.4.1.

This is probably the first time our Qt 5 ports are tracking the latest
upstream release :-)

There isn't much to report in this update, thanks to the effort spent in the
5.2->5.3 update: a lot of the work is just small plist and patch updates.
Thankfully, several patches have been upstreamed and are not needed on our
side anymore.

I would like to thank Alex Richardson <arichardson.kde@gmail.com> and Tobias
Berner <tcberner@gmail.com> for their help with the plist updates and
general testing.

PR: 198585